Molecular Modeling of Double Retrograde Vaporization Using Monte Carlo Simulations and Equations of State. Academic Article uri icon

abstract

  • Vapor-liquid equilibria of binary systems consisting of a low-boiling (i.e., more volatile) and a high-boiling compound may exhibit unexpected behavior near the critical point of the low-boiling compound. Near the critical temperature of the low-boiling compound and for compositions rich in the low-boiling compound, increasing the pressure may result in multiple crossings of the dew- and bubble-point curves. This phenomenon is often called double retrograde vaporization (or condensation) and may play a role in oil field operations and gas transport through pipelines, but the microscopic driving forces for the unusual shape of the dew-point curve are not well understood. Monte Carlo simulations in the constant-pressure, constant-temperature Gibbs ensemble using the united-atom version of the TraPPE force field were carried out for the methane/n-butane mixture at temperatures ranging from 0.95 to 1.05 of the reduced (T/Tc) temperature of methane. The simulations predict a wealth of additional thermodynamic data (densities and free energies of transfer) and structural data that are used to provide much needed molecular-level insights into the fluid properties associated with double retrograde vaporization. Simulated thermodynamic data are also compared with calculations using the Peng-Robinson and PC-SAFT equations of state.

published proceedings

  • J Phys Chem B

author list (cited authors)

  • Corts Morales, A. D., Diamantonis, N., Economou, I. G., Peters, C. J., & Siepmann, J. I.

citation count

  • 0

complete list of authors

  • Cort├ęs Morales, Angel D||Diamantonis, Nikolaos||Economou, Ioannis G||Peters, Cornelis J||Siepmann, J Ilja

publication date

  • April 2023